1. Field of the Invention
The present invention relates to an imaging device, an imaging method, and an image processing device. In particular, the present invention relates to an imaging device, an imaging method, and an image processing device capable of performing restoration processing based on a point spread function.
2. Description of the Related Art
On an image of a subject photographed through an optical system, sometimes, a so-called point spread phenomenon may be observed. The point spread phenomenon is a phenomenon that a point subject is slightly enlarged by an effect such as aberration or diffraction caused by the optical system. A function, which indicates a response to a point light source of the optical system, is referred to as a point spread function (PSF). This function is known as a parameter having an influence on resolution degradation (blurring) of a photographed image.
A photographed image, of which image quality is lowered due to the point spread phenomenon, is subjected to restoration processing (point image restoration processing) based on the PSF, and thereby image quality of the image can be restored. The restoration processing is processing of acquiring degradation characteristics (point image characteristics), which are caused by aberration and the like of the lens (optical system), in advance and canceling out the point spread of the photographed image through image processing using a restoration filter corresponding to the point image characteristics.
There have been proposed various techniques of the restoration processing. For example, JP2009-260622A discloses an imaging device capable of performing processing of recovering a photographed image without degradation in image quality. The imaging device determines a reliability of a point image spread function (point spread function), and performs image recovery processing on the basis of a result of the determination of the reliability.
JP2011-217274A discloses an image recovery device for improving an accuracy of image recovery when a subject distance cannot be obtained from an auto focus mechanism. This image recovery device estimates a subject distance, calculates a recovery filter on the basis of the estimation result, and recovers image data by using the calculated recovery filter.